Twin-Boom Crawler Quadruples Lifting Capacity

Terex-Demag's new CC8800-1 Twin is an impressive crane. Claiming to be the world's largest lattice boom crawler crane that can travel with a load, the machine was shown for the first time at its hand-over ceremony to new owner Al Jaber Heavy Lifting earlier this month.

Steve Filipov, president of Terex Cranes, likened the Twin to a “fine red wine • the longer you wait, the better it gets” • a reference to the eight years taken to develop the crane in association with Al Jaber to meet the increasingly demanding needs of a continually changing lifting industry.

The end result appears to have been worth the wait, giving a crane that is based on the tried and tested components of the CC8800-1, yet with the addition of the double boom gives a 3,527-ton lifting capacity and a maximum load moment of more than 44,000 metre tonnes. This combination gives erection savings in terms of time and space when compared with ring lift cranes and jacking towers.

Alex Mullins, general manager of Al Jaber Heavy Lifting, outlined the long, and at times difficult, birth of the Twin. “In 1999, the largest crane was the [661-ton} capacity CC12600, but due to the changing heavy lifting sector, we could see a demand for a crane with a [2,204-ton] lift capacity,” said Mullins. “So we put this to various manufacturers, but only Demag responded positively offering a CC5800 (1,102 ton) mounted on a ring attachment. Although we rejected this, Demag responded with a CC8800, which in 2002 looked to be a good solution.”

“Changing markets and requirements meant that by 2003 the capacity had to be upped to [3,307 tons] with a redesign of the ring attachments. By 2005, Al Jaber asked for a modular design along the lines of the CC8800-1, so that it would be easily transportable with the heaviest component being [66 tons] and widest [more than 11 feet].”

Terex-Demag had in fact first had the twin boom idea in 1999 based on the CC2800, but it was too costly and the capacity too small. However, over the following years, it had worked with Al Jaber proposing various ring type machines until arriving at the final version.

Twin power

The main feature of the Twin is its double main boom arrangement which increases the lifting capacity of the CC8800-1 by a factor of almost four in certain configurations. Like the main boom, the luffing fly jib and the Superlift mast are also doubled up and connected by cross-bracings and all winches and hook blocks are provided in pairs.

The undercarriage has been extended by a 9.8-foot connecting structure to almost 46 feet wide, which is the base for the 32-foot diameter integrated circular track with roller system. The front superstructure of the CC8800-1 is doubled, whereas the rear frame has been incorporated unchanged.

The counterweight carrier and two Superlift trays of the CC8800-1 are connected into a patented Twin counterweight system of 1,918 tons, allowing the counterweight to be easily adapted to the requirements of the lifting job and achieve the full maneuverability of the crane.

Boom boom

Although only rigged to 223 feet at the handover ceremony, the main boom can be extended up to almost 384 feet long and can be combined with a luffing jib of the same length, resulting in a maximum hook height of more than 770 feet.

For erecting components in petrochemical facilities, a Vessellift is available. Made up of parts of the luffing fly jib, this makes it possible to erect distillation columns of 328 feet in length and weighing up to 1,984 tons.

With transport and assembly as simple as a single boom machine, the parallel boom arrangement reduces rigging times as procedures are just doubled. The Twin also uses the familiar touch screens and joysticks of the Terex-Demag IC-1 control system which includes auto diagnostic functions making it easier to locate faults on-site.

Increased productivity

All standard 1,764-ton CC8800-1s are able to be upgraded with a Twin kit to the full 3,527-ton lift capacity when the Twin kit is fitted. The Twin also has two identical drive units that operate independently and a second independent control system. Should one engine or control system fail • for example as a result of a lightening strike • the CC8800-1 Twin can continue to work.

But the main advantage of the Twin is that it can theoretically pick and carry its full load chart and is mobile when fully rigged. Unlike ring cranes and lifting platforms which impede construction site operations while they are erected on site, the Twin can be erected away from the site and also collect a load and carry it to its final destination.

Terex-Demag has firm orders for two more machines and longer-term expects as many as 10 operating around the world.

CC8800-1 Twin facts and figures

Max capacity: 3,527.4 tons

Max load moment: 43,900 tonne metres @ 59-foot radius

Max transport width of components: 11.48 feet

Max component weight: 66 tons

Max lift on full boom: 271 tons @ 383.85 feet

Total rigged weight: 3,582.5 tons